Throughout the episode, Goofy repeatedly suggests "pineapple" as a cure, inspired by his own "pineapple underpants". While the others try different methods—such as Mickey jumping and counting to 12 or Goofy doing 15 loop-de-loops—Donald remains the only one still hiccuping.
Goofy started jumping rope. Donald watched, trying to count. Hic... hic... Mickey tickled Donald’s beak with the feather. Donald held his breath, eyes watering. Hic— No. Hic— Nothing. Then—silence.
Donald’s Hiccups
But just as Donald reached for his magician’s hat, he gulped down his lemonade too fast. HIC! Donald’s beak twitched. HIC! His whole body shook. HIC-CUP!
As the episode progresses, the gang discovers that the hiccups are caused by Donald drinking a glass of cold water too quickly. They come up with a plan to use the Mousketools to help Donald get rid of the hiccups.